Painter Georgia O'Keeffe and photographer Alfred Stieglitz are among art history's foremost couples. And they left an amazingly detailed record of their relationship in the form of more than 5,000 letters. Sarah Greenough of the National Gallery of Art has edited a new volume of these letters. She joins us to discuss the couple's relationship and their work.

U.S. Food and Drug Administration Commissioner Margaret Hamburg joins us to discuss the role of the FDA in protecting public health, how the agency approves new drugs and her views on what she calls "smart regulation."

The Athena Breast Health Network is launching a series of face-to-face forums where patients, breast cancer experts and community members can exchange direct experience and research in breast health care. The first forum will examine breast cancer risk assessment and prevention - and the results will be fed back into the UC-based Athena Network of 150,000 women to improve survival and reduce suffering from breast cancer.

Nearly 3 million Americans have epilepsy. It's as common as breast cancer, and can be as dangerous. But those with the disease say research is underfunded and epilepsy doesn't get the attention it deserves. We talk with participants in a major conference in San Francisco on emerging treatments for epilepsy.

Researchers at UCSF argue that sugar poses a danger to health and should be regulated like alcohol and tobacco. Is sugar just empty calories, or something much worse?

Aboriginal people in Australia are better at finding their way around because they use compass directions instead of simply describing things as to the left or right. That's just one of several findings from Stanford psychologist Lera Boroditsky, who claims language greatly influences our thoughts and perceptions. It's a radical departure from modern linguistic theory.

Social networking giant Facebook has filed the paperwork to begin selling public shares. The long-anticipated filing is the largest Internet public offering ever. The website, with 845 million users, is expected to be valued at between $75 and $100 billion. We discuss the potential impact of the IPO on users, Silicon Valley and the financial industry.

The dean of San Francisco's Grace Cathedral, Reverend Jane Shaw joins us along with artist-in-residence and performer Anna Deavere Smith to discuss Grace and spirituality.

California's lieutenant governor and former San Francisco mayor Gavin Newsom joins us to discuss the role of the office of the lieutenant governor. And, as a board member of both the University of California and CSU, we'll hear Newsom's ideas about the changes in higher education in California.

Writer and photographer Lisa Hamilton says the lack of direct contact between urban and rural Californians makes it feel as though California is made up of two wholly separate states. In a new project titled "Real Rural," Hamilton and her partners introduce California's unseen rural populations to their urban neighbors through photography, interviews and audio conversations.

President Obama's message to colleges is simple: perpetual tuition hikes are no longer an option. Last week, he promised to reward colleges if they hold the line on tuition increases. On the other hand, he told college administrators that if they don't stop tuition from going up, then the funding they get from taxpayers each year will go down. We discuss the president's proposal.

Egypt recently marked the one-year anniversary of its Arab Spring revolution, which overthrew dictator Hosni Mubarak. Yet, the country remains in turmoil as different factions fight for political power. Steven Cook, a senior fellow at the Council on Foreign Relations, joins us to discuss his new book, "The Struggle for Egypt."

More than 400 people were arrested in clashes with police after a City Hall march and rally Saturday by Occupy Oakland. On Sunday, Mayor Jean Quan decried the damage and said the demonstrations have cost the budget-strapped city more than $5 million. Meanwhile, protesters criticized police conduct, saying the arrests were illegal and that OPD gave them no option to disperse. We discuss the weekend's developments.